Add engine for handling uploads domain

The serving is only used in development - in production it hits CloudFront.

.env.example

@@ -4,3 +4,4 @@ OTP_SECRET_ENCRYPTION_KEY=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 NOTIFY_API_KEY=xxxxx
 GROUPED_PROPOSAL_DETAILS_FEATURE=enabled
 GOOGLE_TAG_MANAGER_ID=GTM-XXXXXXXX
+UPLOADS_BASE_URL=http://uploads.bops.localhost:3000

.env.test

@@ -2,3 +2,4 @@ STAGING_API_URL="bops-staging.services"
 STAGING_API_BEARER="fjisdfjsdiofjdsoi"
 OS_VECTOR_TILES_API_KEY="testtest"
 NOTIFY_LETTER_API_KEY='testtest'
+UPLOADS_BASE_URL=http://uploads.example.com

.github/workflows/build.yml

@@ -77,6 +77,7 @@ jobs:
           - { group: "bops_api", module: "engines" }
           - { group: "bops_config", module: "engines" }
           - { group: "bops_core", module: "engines" }
+          - { group: "bops_uploads", module: "engines" }
       fail-fast: false
     with:
       name: "${{matrix.specs.group}}"

.rspec

@@ -2,4 +2,5 @@
 -I engines/bops_admin/spec
 -I engines/bops_api/spec
 -I engines/bops_config/spec
+-I engines/bops_uploads/spec
 --require spec_helper

Gemfile

@@ -56,6 +56,7 @@ gem "bops_core", path: "engines/bops_core"
 gem "bops_admin", path: "engines/bops_admin"
 gem "bops_api", path: "engines/bops_api"
 gem "bops_config", path: "engines/bops_config"
+gem "bops_uploads", path: "engines/bops_uploads"
 
 group :development, :test do
   gem "brakeman", require: false

Gemfile.lock

@@ -28,6 +28,12 @@ PATH
       pagy
       rails (>= 7.1.3, < 7.2)
 
+PATH
+  remote: engines/bops_uploads
+  specs:
+    bops_uploads (0.1.0)
+      bops_core (= 0.1.0)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -668,6 +674,7 @@ DEPENDENCIES
   bops_api!
   bops_config!
   bops_core!
+  bops_uploads!
   brakeman
   bullet
   business_time

Makefile

@@ -51,7 +51,10 @@ config-specs:
 core-specs:
 	$(DOCKER-RUN) console rspec engines/bops_core/spec
 
-engine-specs: api-specs admin-specs config-specs core-specs
+uploads-specs:
+	$(DOCKER-RUN) console rspec engines/bops_uploads/spec
+
+engine-specs: api-specs admin-specs config-specs core-specs uploads-specs
 
 rspec:
 	$(DOCKER-RUN) console rspec

app/models/document.rb

@@ -24,7 +24,7 @@ class NotArchiveableError < StandardError; end
     inverse_of: false
 
   delegate :audits, to: :planning_application
-  delegate :representable?, to: :file
+  delegate :blob, :representable?, to: :file
 
   include Auditable
 

config/application.rb

@@ -74,6 +74,7 @@ class Application < Rails::Application
     config.planx_file_production_api_key = ENV["PLANX_FILE_PRODUCTION_API_KEY"]
     config.staging_api_bearer = ENV["STAGING_API_BEARER"]
     config.staging_api_url = ENV["STAGING_API_URL"]
+    config.uploads_base_url = ENV["UPLOADS_BASE_URL"]
   end
 
   def self.env

config/routes.rb

@@ -378,6 +378,10 @@
     mount BopsConfig::Engine, at: "/", as: :bops_config
   end
 
+  constraints Constraints::UploadsSubdomain do
+    mount BopsUploads::Engine, at: "/", as: :bops_uploads
+  end
+
   direct :rails_public_blob do |blob|
     if (cdn_host = ENV["CDN_HOST"])
       # Use an environment variable instead of hard-coding the CDN host

engines/bops_uploads/app/controllers/bops_uploads/application_controller.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module BopsUploads
+  class ApplicationController < ActionController::Base
+  end
+end

engines/bops_uploads/app/controllers/bops_uploads/files_controller.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module BopsUploads
+  class FilesController < ApplicationController
+    before_action :set_service
+    before_action :set_blob
+
+    def show
+      serve_file(blob_path, content_type:, disposition:)
+    rescue Errno::ENOENT
+      head :not_found
+    end
+
+    private
+
+    def set_service
+      @service = ActiveStorage::Blob.service
+    end
+
+    def set_blob
+      @blob = ActiveStorage::Blob.find_by!(key: params[:key])
+    end
+
+    def blob_path
+      @service.path_for(@blob.key)
+    end
+
+    def forcibly_serve_as_binary?
+      ActiveStorage.content_types_to_serve_as_binary.include?(@blob.content_type)
+    end
+
+    def allowed_inline?
+      ActiveStorage.content_types_allowed_inline.include?(@blob.content_type)
+    end
+
+    def content_type
+      forcibly_serve_as_binary? ? ActiveStorage.binary_content_type : @blob.content_type
+    end
+
+    def disposition
+      if forcibly_serve_as_binary? || !allowed_inline?
+        :attachment
+      else
+        :inline
+      end
+    end
+
+    def serve_file(path, content_type:, disposition:)
+      ::Rack::Files.new(nil).serving(request, path).tap do |(status, headers, body)|
+        self.status = status
+        self.response_body = body
+
+        headers.each do |name, value|
+          response.headers[name] = value
+        end
+
+        response.headers.except!("X-Cascade", "x-cascade") if status == 416
+        response.headers["Content-Type"] = content_type || DEFAULT_SEND_FILE_TYPE
+        response.headers["Content-Disposition"] = disposition || DEFAULT_SEND_FILE_DISPOSITION
+      end
+    end
+  end
+end

engines/bops_uploads/bin/rails

@@ -0,0 +1,19 @@
+#!/usr/bin/env ruby
+# This command will automatically be run when you run "rails" with Rails gems
+# installed from the root of your application.
+
+ENGINE_ROOT = File.expand_path("..", __dir__)
+ENGINE_PATH = File.expand_path("../lib/bops_uploads/engine", __dir__)
+APP_PATH = File.expand_path("../../../config/application", __dir__)
+
+# Set up gems listed in the Gemfile.
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../../Gemfile", __dir__)
+require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
+
+require "rails"
+
+require "active_model/railtie"
+require "active_record/railtie"
+require "action_controller/railtie"
+require "action_view/railtie"
+require "rails/engine/commands"

engines/bops_uploads/bops_uploads.gemspec

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+Gem::Specification.new do |spec|
+  spec.name = "bops_uploads"
+  spec.version = "0.1.0"
+  spec.authors = ["Unboxed Consulting Ltd"]
+  spec.email = ["[email protected]"]
+  spec.homepage = "https://unboxed.co/"
+  spec.summary = "Provides the uploads facility for the BOPS system"
+
+  spec.files = Dir.chdir(File.expand_path(__dir__)) do
+    Dir["{app,config,db,lib}/**/*"]
+  end
+
+  spec.add_dependency "bops_core", "0.1.0"
+end

engines/bops_uploads/config/routes.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+BopsUploads::Engine.routes.draw do
+  get "/:key", to: "files#show", as: "file"
+end
+
+Rails.application.routes.draw do
+  direct :uploaded_file do |blob, options|
+    next "" if blob.blank?
+
+    bops_uploads.file_url(blob.key, host: Rails.configuration.uploads_base_url)
+  end
+
+  resolve("ActiveStorage::Attachment") { |attachment, options| route_for(:uploaded_file, attachment.blob, options) }
+  resolve("ActiveStorage::Blob") { |blob, options| route_for(:uploaded_file, blob, options) }
+  resolve("ActiveStorage::Preview") { |preview, options| route_for(:uploaded_file, preview, options) }
+  resolve("ActiveStorage::VariantWithRecord") { |variant, options| route_for(:uploaded_file, variant, options) }
+  resolve("ActiveStorage::Variant") { |variant, options| route_for(:uploaded_file, variant, options) }
+end

engines/bops_uploads/lib/bops_uploads.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require "bops_uploads/engine"
+
+module BopsUploads
+  class << self
+    def env
+      ActiveSupport::StringInquirer.new(ENV.fetch("BOPS_ENVIRONMENT", "development"))
+    end
+  end
+end

engines/bops_uploads/lib/bops_uploads/engine.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module BopsUploads
+  class Engine < ::Rails::Engine
+    isolate_namespace BopsUploads
+  end
+end

engines/bops_uploads/spec/bops_uploads_helper.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.configure do |config|
+  config.before type: :request do
+    host!("uploads.bops.services")
+  end
+end

engines/bops_uploads/spec/requests/files_spec.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "bops_uploads_helper"
+
+RSpec.describe "Downloading files", show_exceptions: true do
+  context "when a blob exists" do
+    let(:document) { create(:document) }
+    let(:blob) { document.file }
+    let(:key) { blob.key }
+    let(:path) { blob.service.path_for(blob.key) }
+
+    it "returns 200 OK" do
+      get "/#{key}"
+      expect(response).to have_http_status(:ok)
+      expect(response.content_type).to eq("image/png")
+    end
+
+    context "but the file is missing" do
+      before do
+        File.unlink(path)
+      end
+
+      it "returns 404 Not Found" do
+        get "/#{key}"
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+  end
+
+  context "when a blob doesn't exist" do
+    let(:key) { SecureRandom.base36(28) }
+
+    it "returns 404 Not Found" do
+      get "/#{key}"
+      expect(response).to have_http_status(:not_found)
+    end
+  end
+end

lib/constraints/subdomain.rb

@@ -24,4 +24,12 @@ def matches?(request)
       end
     end
   end
+
+  class UploadsSubdomain
+    class << self
+      def matches?(request)
+        request.subdomain == "uploads"
+      end
+    end
+  end
 end

spec/support/show_exceptions.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+RSpec.configure do |config|
+  config.around(:each, type: :request) do |example|
+    if example.metadata.key?(:show_exceptions)
+      begin
+        env_config = Rails.application.env_config
+        show_exceptions = env_config["action_dispatch.show_exceptions"]
+        env_config["action_dispatch.show_exceptions"] = example.metadata[:show_exceptions] ? :all : :none
+
+        example.run
+      ensure
+        env_config["action_dispatch.show_exceptions"] = show_exceptions
+      end
+    else
+      example.run
+    end
+  end
+end